1. Field of the Invention
The present invention relates to a calibration method, an information processing apparatus and an information processing system, and more specifically to a calibration performed for stably keeping at a desired level a print characteristic of a printing apparatus, such as color printer, connected through network to an information processing apparatus, such as personal computer.
2. Description of the Related Art
Generally, it may occur that a print characteristic of a printing apparatus changes depending on environmental conditions, such as temperature and humidity, under which the apparatus is used. It is also known that the print characteristic may change after a certain period of use of the printing apparatus. In the printing apparatus of an electrophotographic system, for example, a photosensitivity characteristic of a photosensitive drum have changed due to the environmental conditions or after use of the printing apparatus and then the print characteristic observed in a printed image, such as a gradation of the printed image changes from a desired one. On the other hand, in a printing apparatus of an ink jet system, it is also known that an ejection characteristic change of a print head may cause the print characteristic to be changed.
The calibration is performed to correct such a change in the print characteristic, but it is not performed only for the change that occurs in an individual printing apparatus. For example, in an information processing system using a plurality of printing apparatus, the print characteristic differences among the plurality of printing apparatus pose a problem. Also in such a case, the calibration is performed to reduce variations of print characteristic among the printing apparatuses.
In conventional execution of such calibration, the calibration is basically executed according to instructions by a user of the printing apparatus, the information processing system or the like. For example, when the user observes that the gradation of the printed image is not a desired one, the user instructs the printing apparatus or a personal computer to execute the calibration through an operation display displayed by the printing apparatus or the personal computer (or simply referred to as “PC”).
With the above-described conventional execution of the calibration, however, an appropriate calibration may not be performed responsively to and in matching with the change in the print characteristic, which occurs at that time. More specifically, because the user sets execution timing of the calibration in the conventional execution, the calibration is not performed when the user does not notice the print characteristic change or when the user, if he notices the change, does not think the calibration necessary. In other words, it is not easy to manage the calibration execution timing uniformly, giving rise to a problem of frequent occurrence of density variations or color variations in the printed images.
Particularly in a printing system using a plurality of printing apparatuses interconnected through a network, it is general that there are many users using these printing apparatuses and thus the problem that the execution timing cannot be managed uniformly becomes more significant. In a system using the plurality of printing apparatuses, differences in the print characteristic itself or in the print characteristic change among the printing apparatuses, in combination with the above problem, will pose a serious problem in terms of print quality. That is, if the printing is done based on the same print data, the density and hue of the printed result will differ from one apparatus to another.